Bulldozer blade load equalizer

ABSTRACT

An apparatus for relieving and equalizing the stresses generated in the bracing and push arms of a bulldozer when the blade is adjusted to its tilt position and subjected to side load forces during operation, the described embodiment including diagonal braces mounted in a unitary fixture which is slidably associated with a fixed housing on said blade and limited to movement in directions normal to said blade.

O United States Patent [15] 3,647,006

Kallenbach 1 Mar. 7, 1972 [54] BULLDOZER BLADE LOAD 3,049,820 8/1962 Lichti ..l72/803 EQUALIZER 3,187,448 6/1965 Kolinger 3,234,670 2/1966 Fryer et al. ..l72/803 [72] Inventor: Ralph M. Kallenbach, 915 Carol, Elgin,

111. 60120 Primary ExaminerRobert E. Pulfrey Assistant Examiner-Stephen C. Pellegrino [22] Filed May 1969 Attorney-Pendleton, Neuman, Williams & Anderson [21] Appl. No.: 824,829

[57] ABSTRACT [52] US. Cl ..l72/803, [72/806, 172/809 An apparatus for relieving and equalizing the stresses [51] Int. Cl. ..E02f 3/76 generated in the bracing and P arms of a bulldozer when 58 Field of Search ..172/803, 801, 804, 806 the blade is adjusted to its till Position and subjected to side load forces during operation, the described embodiment in- R f cluding diagonal braces mounted in a unitary fixture which is [56] e 0 ed slidably associated with a fixed housing on said blade and UNITED STATES PATENTS limited to movement in directions normal to said blade.

3,025,620 3/1962 Liess ..l72/803 1 Claims, 5 Drawing Figures .21 M n i l ii... 1. a n 'W "W W llll \llll' llll Z6 T "F O 'l H: O

BULLDOZER BLADE LOAD EQUALIZER BACKGROUND OF THE INVENTION I. Field of the Invention This invention relates in general to bulldozers, and in particular, to bulldozers having tiltable blades. Tilting of a bulldozer blade generates stresses in both the diagonal braces and the push arms which support the blade. The nature of the stresses in the diagonal braces are principally compressive, and these compressive stresses are in turn borne as bending stresses by the push arms to which one end of the diagonal braces are connected. During operation of the bulldozer with its blade in the tilted position, additional side load forces on the blade are often encountered and these additional forces, coupled with the stresses imparted by tilting the blade, may be sufficient to result in failure of a push arm. The present invention provides an apparatus for relieving the tilt stresses and for equalizing the side load stresses in the push arms.

2. Description of the Prior Art Solutions have been sought for some time for the problem which the present invention solves, and consequently, various other less satisfactory solutions have been proposed including: a universal connection between the inner ends of the diagonal braces; a direct connection between the ends of the diagonal braces wherein the end of one brace is slidably mounted in a trunnion fixed to the end of the other brace; and a system wherein a torsion bar is used to connect the ends of the diagonal braces. The principal vice of the prior art is that every embodiment necessitates the use of a multiplicity of components thereby increasing the possibility of mechanical failure under the high stresses encountered during operation. It is axiomatic that, all other factors being equal, the greater the number of components in an apparatus, the greater the possibility that one will fail. The present invention discloses a system which uses a minimum number of parts to perform the functions of both relieving the tilt stresses in, and balancing the operational side loads on, the push arms of a bulldozer.

SUMMARY OF THE INVENTION The present invention provides a unitary fixture to which the ends of the diagonal braces, distal from the push arms, are connected. The fixture is in turn slidably mounted within a housing on the bulldozer blade for movement only in directions normal to the bulldozer blade. This construction provides maximum durability at minimum cost while further allowing the slideway for the fixture within the housing to be readily shielded from the destructive effects of dust and debris.

It is an object of this invention, therefore, to provide a bracing system for a bulldozer blade whereby stresses created by tilting the blade may be relieved, and whereby stresses generated by side loads may be equally distributed between the push arms. More specifically, it is an object of the present invention to provide a stress relieving fixture to receive and hold the converging ends of the diagonal braces which extend from connections with the bulldozer push arms. It is a further object to provide such a fixture having a maximum durability and a minimum number of parts.

Further and additional objects of the invention will become manifest from this description, the accompanying drawing, and the appended claims.

DESCRIPTION OF THE DRAWING For a more complete understanding of this invention reference will now be made to the accompanying drawing wherein:

FIG. 1 is a plan view of a tractor with a bulldozer embodying the present invention;

FIG. 2 is a fragmentary plan view of the fixture and housing of the present invention;

FIG. 3 is a fragmentary elevation view taken along the linc33 in FIG. I;

FIG. 4 is a rear perspective view of the housing of the present invention; and

FIG. 5 is a front perspective view of the fixture of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, and particularly to FIG. 1, a conventional tractor 10, having a bulldozer generally in dieated as 11 mounted thereon, is shown. Bulldozer 11 includes a blade 12 which is supported in part by push arms 13. The push arms 13 are connected at one end to the blade 12 by means of hinge connections 14 and at their other end to the tractor 10 by means of hinge connections 15. It is understood that either or both of these hinge connections could be replaced by conventional baIl-and-socket-type joints or the equivalent thereof. In the disclosed embodiment, conventional hydraulic lift jacks 16 are provided for raising and lowering the blade. The lift jacks being connected to thetractor 10 by means of brackets 17, and to the blade 12 by m'eans of hinge joints 18. The present invention is likewise applicable, however, to other embodiments wherein raising or lowering of the blade is accomplished by means of cables or other conventional means.

The blade 12 is held in an erect position by the cooperation of the connection 14 between the push arm and the blade and tilt braces 19 and 20 (see FIG. 3). Tilt braces 19 and 20 extend between hinges 21 on the tops of push arms 13 and dozer blade support arrangements, these diagonal braces are generally connected directly-to the rear of the blade by means of ball and socket joints. Fixture 25 includes hemispherical sockets 26 (FIG. 5) on two of its faces 27, which sockets are adapted to receive balls 28 disposed on the converging ends of diagonal braces 23. Plates 29 (FIG. 2) are then fastened to fixture 25 by means of screws, or other conventional fastening means, tohold balls 28 within sockets 26.

Fixture 25 is a unitary metal block which, besides having faces 27 bearing sockets 26, has keyways 30 disposed on its top and bottom, and is of a size such that it may be disposed for sliding movement within housing 31 (FIG.'4). Housing 31 is mounted on the back of blade 12, an includes keys 32 which engage and cooperate with keyways 30 to limit movement of the fixture in directions normal to blade 12. It is understood that the location of the keys and keyways could be reversed with respect to the fixture and housing, or that a greater or lesser number of keys and keyways could be provided at different positions and still be within the scope of the present invention.

The structure of the conventional tilt blade bulldozer as well as the structure of the present invention, having been thus described, it is seen that tilting of bulldozer blade 12 is accomplished by shortening or lengthening tilt brace 19 by extending thereto, to be raised, and in the conventional structure, places diagonal braces 23 in compression. The compression loads in diagonal braces 23 are, in turn, transferred to push arms 13 through connections 24, thereby creating a bending stress in said push arms and a bending movement about hinges 15. Thus it is seen that the bulldozer blade support is under significant stress even before earthmoving operations are begun. During use, side loads, such as that illustrated by arrow A (FIG. 1), are often encountered which place the diagonal brace opposed thereto (brace B, FIG. 1) under additional compression load while placing diagonal brace C (FIG. I) in tension, thereby relieving the compression stress generated therein during tilting. This compression stress in brace B is again transferred to the push arm associated therewith, and places a bending stress thereon. This side load stress coupled with the stress placed on the supports during tilting results in a bending stress in the push arm which may be large enough to cause failure to occur either in the push arm, at hinge 15, or at some other point in the structure.

In the present invention, fixture 25 is slidably mounted in housing 31 on the rear of blade 12. Upon tilting of the blade, the compressive stresses generated in the diagonal braces, and consequently the bending stresses in the push arms, are relieved by the sliding of fixture 2S forward in housing 31. Fixture 25 being a solid unitary piece limited to movement only in directions normal to blade 12, and, in addition, being fitted closely within housing 31, no twisting, tilting or shearing may occur therein, and the sliding action of the fixture within the housing is very smooth. Upon the additional application of side loads to the blade, the compressive stresses in diagonal brace B and the tensile stresses in diagonal brace C are equalized by the transmission of the stresses in each diagonal brace to the other diagonal brace through the solid, ball and socket connections with fixture 25. The strength of fixture 25 and its stability of movement within housing 31, gives the entire blade support structure its unique ability to sustain heavy side loads without danger of collapse, while transmitting these forces on the blade to the blade support structure and equalizing them therein.

While one particular embodiment of the invention has been described in detail it will immediately appear that modifications may be incorporated without departing from the spirit and scope of this invention. For instance, the shape of fixture 25 could be altered to more completely fill the housing 31, thus providing better protection for the slide mechanism from stones or other debris encountered during operation. Alternatively, flexible sleeves could be attached around diagonal braces 23 and to the front openings of housing 31 to attain the same end.

The invention having thus been described, what is desired to be claimed by letters patent is:

1. In a bulldozer comprising a blade, push arms connected to said blade, means for tilting said blade connected between said blade and said push arms, and diagonal braces extending from said push arms towards said blade, apparatus for relieving tilt stresses and equalizing side loads including, constricting means connected to the rear of said blade, said constricting means having at least two vertically disposed bearing surface and at least two horizontally disposed bearing surfaces, a fixture held by said constricting means and having surfaces cooperating with the aforesaid bearing surfaces, said fixture being constricted to sliding movement along an essentially straight line path normal to said blade, said fixture further including two connection means horizontally displaced from one another in a direction normal to the fixture's direction of movement for individually connecting the inboard ends of the diagonal braces to separate points of said fixture, wherein the fixture and constricting means include associated keys and keyways, and the movement of the fixture within the constricting means is a sliding movement. 

1. In a bulldozer comprising a blade, push arms connected to said blade, means for tilting said blade connected between said blade and said push arms, and diagonal braces extending from said push arms towards said blade, apparatus for relieving tilt stresses and equalizing side loads including, constricting means connected to the rear of said blade, said constricting means having at least two vertically disposed bearing surface and at least two horizontally disposed bearing surfaces, a fixture held by said constricting means and having surfaces cooperating with the aforesaid bearing surfaces, said fixture being constricted to sliding movement along an essentially straight line path normal to said blade, said fixture further including two connection means horizontally displaced from one another in a direction Normal to the fixture''s direction of movement for individually connecting the inboard ends of the diagonal braces to separate points of said fixture, wherein the fixture and constricting means include associated keys and keyways, and the movement of the fixture within the constricting means is a sliding movement. 